Chlorine dioxide, or ClO2 is a well known biocide that has been discussed as an agent to extend the storage life of goods. An efficient way to apply ClO2 gas and to treat such goods is to use it to fumigate the goods in the areas in which they are stored and/or transported. Examples of such areas include shipping containers on ocean transport vessels, freight holds of ocean transport vessels, the trailer section of motor freight trucks, and various warehouse enclosures. However, it can be dangerous to treat such spaces with ClO2 gas due to the inhalation toxicity of ClO2. Illness or death can result if a human enters the treated space when the ClO2 gas concentration is above safe levels.